How Diverticulitis Affects the Sigmoid Colon

The digestive system relies on the colon to pull water, nutrients, and electrolytes from partially digested food, leaving the rest as waste. Diverticulitis occurs when sacs form throughout the colon and push through weak spots of the colon wall, leading to inflammation and infection. Diverticulitis is most commonly found in the S-shaped part of the intestines, known as the sigmoid colon.

This article discusses the colon, how it works, and how diverticulitis can affect this part of the digestive system.

Nurse prepping for digestive surgery


Understanding How the Colon Works

The colon is a vital part of the digestive system. Otherwise known as the large bowel or large intestine, the colon plays various roles in digestion, including:

  • Absorbing water, nutrients, and electrolytes from partially digested food
  • Breaking down the remaining food material
  • Moving what is left over, known as waste or stool, into the rectum

When the food has made its way through the colon, the body can excrete it.

Sigmoid Colon Definition

The sigmoid colon is the S-shaped part of the large intestine that connects to the rectum.  

The Sigmoid Colon and Diverticulitis

Diverticulitis is a condition that develops when diverticula, the small sacs that can form in the large intestine, push through weakened areas of the colon wall. These sacs become inflamed and infected. Though diverticula can form throughout the intestines, they are most likely to develop in the sigmoid colon.

The presence of diverticula doesn’t necessarily signal an issue, and many people can have these pouches without experiencing any adverse effects on their health.

It’s only a problem when these sacs become inflamed. The symptoms and adverse health effects of diverticulitis can be severe.

How Common Is Diverticulitis?

Diverticulitis affects many individuals and is considered one of the most prevalent types of bowel issues that result in a visit to the emergency room. Roughly 3.8% of people visiting the ER due to abdominal pain have diverticulitis.

Signs of Diverticulitis

When a person develops diverticulitis in the sigmoid colon, they may develop acute symptoms such as:

  • Pain in the lower left side of the abdomen
  • Pain that comes on suddenly and feels severe or pain that begins mildly and continues to worsen over a few days
  • Pain that changes in intensity
  • Gastrointestinal issues such as diarrhea or constipation
  • Fevers or chills
  • Nausea
  • Vomiting

If the symptoms are not addressed, complications can become life-threatening.

In some cases, diverticulitis can become severe and lead to dangerous health complications, including:

  • Perforation of the intestinal wall
  • Abscess in the pouches, which is a collection of pus that occurs due to an infection
  • Pylephlebitis, which is inflammation of a vein in the abdomen known as the portal vein
  • Bowel obstruction, which is a blockage in the intestines
  • Hemorrhage, which is bleeding from the area
  • Fistulas, which are abnormal connections (e.g., if the intestine attaches to an organ by mistake)

How Is Diverticulitis Diagnosed?

The steps for diagnosing diverticulitis are:

  • Taking an account of your medical history
  • Performing a physical exam
  • Ordering the appropriate tests

For your medical history, your medical provider will want to know your symptoms, what you eat and drink, and your bowel habits. During the medical history collection, they must also note existing health conditions and medications.

During the physical exam, your medical provider will listen for sounds in your abdomen that could help them determine what tests you need and press on areas of the stomach to feel for any mass of tissue or areas of tenderness. After they have done that, they will order tests.

Some tests that diagnose diverticulitis include:

After testing, a medical provider may want to perform a colonoscopy to confirm whether a person has diverticulitis or something else. A colonoscopy involves using a scope (a long and narrow tube with a camera attached to the end of it) to go through the intestines and check for issues.

Sigmoidoscopy and Sigmoid Diverticulitis

Sometimes, a medical provider will perform a sigmoidoscopy if they suspect the sigmoid is affected. It is the same type of procedure as a colonoscopy but only checks the sigmoid area.

Other Conditions That Impact the Sigmoid Colon

Several health conditions other than diverticulitis can impact the integrity of the sigmoid colon, including:

How Can You Tell the Difference Between Diverticulitis and Something Else?

It can be hard to tell what’s going on within your abdomen when you experience symptoms that could be both diverticulitis and another gastrointestinal issue. The only proper way to know if you have diverticulitis or another type of intestinal issue is by seeing your medical provider for the appropriate tests.

When to Seek Care

If you experience any of the symptoms mentioned above, you should contact your healthcare provider. Though many of them can be non-specific, they signify that something may need your attention. With diverticulitis, it’s always better to be safe and have it checked out if you have severe abdominal pain because the condition can lead to severe and possibly life-threatening complications.


The sigmoid colon is the S-shaped area of the intestine. It works to help pull water and nutrients into the body from food while passing the rest down through the digestive tract as waste. When the sigmoid colon develops little pouches, known as diverticula, those pouches can push through weak areas of the intestinal wall and can become inflamed and infected.

Though not everyone with these pouches experiences symptoms, some do. Symptoms can include abdominal pain, nausea and vomiting, and digestive issues. If untreated, severe complications can arise, such as bowel obstruction, abscess, or excessive bleeding.

If you experience any of the symptoms above and are unsure where they come from, you must contact your healthcare provider to investigate the problem. Though other conditions can present with the same symptoms, it’s always better to be safe when dealing with abdominal issues.

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. The American Society of Colon and Rectum Surgeons. The colon: what it is, what it does, and why it is important.

  2. National Institute of Diabetes and Digestive and Kidney Diseases. Definition & facts for diverticular disease.

  3. Onur MR, Akpinar E, Karaosmanoglu AD, et al. Diverticulitis: a comprehensive review with usual and unusual complications. Insights Imaging. 2017 Feb;8(1):19-27. doi:10.1007/s13244-016-0532-3

  4. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms & causes of diverticular disease.

  5. National Institute of Diabetes and Digestive and Kidney Diseases. Diagnosis of diverticular disease.

  6. Johns Hopkins Medicine. Sigmoidoscopy.

  7. National Institute of Diabetes and Digestive and Kidney Diseases. Hirschsprung disease.

  8. Wehkamp J, Götz M, Herrlinger K, et al. Inflammatory bowel disease: Crohn's disease and ulcerative colitis. Dtsch Arztebl Int. 2016 Feb 5;113(5):72-82. doi:10.3238/arztebl.2016.0072

  9. Islam S, Hosein D, Bheem V, Dan D. Synchronous volvulus of the sigmoid colon and caecum, a very rare cause of large bowel obstruction. BMJ Case Rep. 2016 Oct 14;2016:bcr2016217116. doi:10.1136/bcr-2016-217116

By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.